Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a mounting board for a multilayer ceramic capacitor.
Description of the Related Art
A multilayer ceramic capacitor, a multilayer chip electronic component, is a chip type capacitor commonly mounted on printed circuit boards of various electronic products, such as image display devices including a liquid crystal display (LCD), a plasma display panel (PDP) and the like, computers, personal digital assistants (PDAs), mobile phones, and the like, and serving to charge or discharge electricity.
Multilayer ceramic capacitors (MLCCs) may be used as components of various electronic products due to having the advantages of a small size, high capacitance, and ease of mounting.
Multilayer ceramic capacitors may have a structure in which a plurality of dielectric layers are stacked and internal electrodes having different polarities are alternately interposed therebetween.
Since these dielectric layers have piezoelectricity properties and electrostrictive properties, a piezoelectric phenomenon may occur and thus cause vibrations between the internal electrodes when AC or DC voltage is applied to the multilayer ceramic capacitor.
Such vibrations may be transferred to a printed circuit board having the multilayer ceramic capacitor mounted thereon through external electrodes of the multilayer ceramic capacitor, such that the overall printed circuit board becomes an acoustic reflective surface to generate a vibratory sound regarded as noise.
The vibratory sound may correspond to an audible frequency in a region of 20 to 20,000 Hz, which may cause listener discomfort and is referred to as acoustic noise.
In order to reduce acoustic noise, a product having a form in which a lower cover layer of the multilayer ceramic capacitor has an increased thickness has been researched.
However, when the thickness of the lower cover layer of the multilayer ceramic capacitor is increased, delamination may occur in a boundary surface between an active layer including the internal electrodes and the lower cover layer, due to a difference in a sintering shrinkage behavior.
In order to prevent the delamination, a multilayer ceramic capacitor having a structure in which dummy electrode terminals exposed in the same direction are formed in the lower cover layer has been disclosed.
However, the multilayer ceramic capacitor having dummy electrode terminals may have a defect in that a step between a region in which the internal electrodes of an active layer overlap each other and a region of longitudinal margin portions of the dummy electrode terminal thereof is increased, and thus, delamination may occur in the longitudinal margin part.
The following Patent Document 1 discloses content in which the thickness of the lower cover layer of the multilayer ceramic capacitor is increased, but does not disclose a structure in which the lower cover layer includes a dummy electrode.